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Worksheets

Chemical Reactions Review

Total questions: 50

Worksheet time: 27mins

Name
Class
Date
1.

The products of a chemical reaction are on the

a)

Left side (Products → Reactants)

b)

Right side (Reactants → Products)

2.

The reactants of a reaction are on the

a)

Left side (Reactants → Products)

b)

Right side (Products → Reactants)

3.

The law of conservation of mass states that

a)

The mass of a system (reaction) increases from beginning to end

b)

The mass of a system (reaction) stays the same from beginning to end

c)

The mass of a system (reaction) decreases from beginning to end

4.

Is this equation balanced? 
(Are there the same amount of H and O atoms on both sides of the equation?)

   H2O2 H2O + O2H_2O_2\rightarrow\ H_2O\ +\ O_2  

a)

Yes

b)

No

5.

A precipitate is

a)

Rain

b)

Snow

c)

A solid formed in a chemical reaction

d)

Condensation formed in a chemical reaction

6.

Chemical reactions happen when

a)

Liquids evaporate

b)

Bonds break or form

c)

Chemicals get heated

d)

Bonds get stretched

7.

In the diagram, letter D represents a

a)

subscript

b)

coefficient

c)

product

d)

equation

8.

In the diagram, letter E represents a

a)

subscript

b)

coefficient

c)

product

d)

equation

9.
Which are the reactants in the equation shown?
a)
H2O and CO2
b)
O2 and CH4
10.

Which is the product in the reaction shown?

a)

Al2O3

b)

Al

c)

O2

11.
What describes the reactant atoms in the equation shown?
a)
Al= 4, O= 3
b)
Al= 1, O= 1
c)
Al= 4, O= 6
d)
Al= 6, O= 1
12.

How does the mass of products compare to the mass of reactants in a chemical reaction?

a)

reactants = products

b)

reactants > products

c)

reactants < products

13.

In the reaction shown below, 12 grams of AB break down into 8 grams of product A and an unknown amount of product B.


Using the law of conservation of mass, what will the mass of product B be?

a)

4 grams

b)

8 grams

c)

12 grams

d)

20 grams

14.
How many Sodium (Na) are in 6NaCl?
a)
1
b)
12
c)
6
15.
How many elements are in C6H12O6?
a)
1
b)
3
c)
12
d)
24
16.
Which of the following is a sign that a chemical reaction has occurred?
a)
change in shape
b)
melting
c)
formation of a gas
d)
dissolving
17.
Is burning wood a chemical or physical change?
a)
chemical
b)
physical
18.

The law of conservation of mass can be demonstrated by a chemical reaction. Which of the following models of a chemical reaction best represents the law of conservation of mass?

a)
b)
c)
d)
19.
This appears on the left side of a chemical formula, and represents how many molecules there are. 
a)
An Atom
b)
The Subscript
c)
A Molecule
d)
The Coefficient
20.
This is used to represent the number of each atom being represented. 
a)
A Exponent
b)
The Coefficient
c)
A Molecule
d)
The Subscript
21.

How many Oxygen (O) atoms are in one molecule of 2C2HO8Cl2

a)

2

b)

16

c)

8

d)

5

22.

The process in which one or more substances are changed into new substances with different chemical and physical properties is called a _____

a)

chemical equation

b)

chemical reaction

c)

stoichiometry

d)

physical change

23.

What are the original substances in a chemical reaction called?

a)

solutions

b)

reactants

c)

products

d)

polyatomic ions

24.

What are the NEW substances produced in a chemical reaction called?

a)

reactants

b)

products

c)

polyatomic ions

d)

solutions

25.

Which of the following is not an indication of a chemical reaction taking place.

a)

color change

b)

odor change

c)

precipitate formation

d)

evaporation

26.

Balance the following equation.

Al + S--> Al2S3

a)

2,2,1

b)

2,4,1

c)

2,3,1

d)

3,1,1

27.

Identify the product(s) in this chemical reaction.

Ca + F2 --> CaF2

a)

Ca

b)

F2

c)

CaF2

d)

Ca and F2

28.

Select the coefficients to balance the following equation.

___Al + ___Ag(NO3) --> __Ag + __Al(NO3)3

a)

3,1,1,3

b)

1,3,3,1

c)

1,2,2,1

d)

2,1,1,2

29.

Anything that has mass and takes up space

a)

Matter

b)

Atom

c)

Molecule

d)

Crystal

30.

two or more atoms bonded together

a)

Matter

b)

Atom

c)

Molecule

d)

Crystal

31.

A substance made up of atoms of two or more different elements joined by chemical bonds

a)

Compound

b)

Coefficient

c)

Subscript

d)

Chemical Formula

32.

A number in front of a chemical formula in an equation that indicates how many molecules or atoms of each reactant and product are involved in a reaction

a)

Compound

b)

Coefficient

c)

Subscript

d)

Chemical Formula

33.

Symbols that show the elements in a compound and the ratio of atoms

a)

Compound

b)

Coefficient

c)

Subscript

d)

Chemical Formula

34.

characteristics used to describe a substance

a)

Properties

b)

Chemical Property

c)

Physical Property

d)

Chemical Reaction

35.

the amount of matter in an object

a)

Product

b)

Conserve

c)

Mass

d)

Law of Conservation of Matter

36.

What is a product (in chemical reactions)?

a)

Something a company will try to sell to you

b)

Also a potato

c)

When the mitosis space-time folds into a tetrahedron flux-capacitor

d)

The substance(s) that are created after a chemical reaction

37.

What is an atom?

a)

Water is an atom

b)

The Hydrogen (H)s and the Oxygen (O)s are atoms

c)

The H2O is an atom

d)

None of these are atoms

38.

What is a molecule?

a)

The H2O is a molecule

b)

The Hydrogen (H)s and the Oxygen (O)s are molecules

c)

The H2O is an atom

d)

None of these are molecules

39.

According to the Law of Conservation of Mass,

a)

matter is always created in a chemical reaction

b)

matter is always destroyed in a chemical reaction

c)

matter is created and then destroyed in a chemical reaction

d)

matter is not created or destroyed in a chemical reaction

40.

The law of conservation of mass can be demonstrated by a chemical reaction. Which of the following models of a chemical reaction best represents the law of conservation of mass?

a)
b)
c)
d)
41.

When carbon and oxygen combine chemically, the mass of the product is

a)

greater than the mass of the carbon plus the mass of the oxygen

b)

equal to the mass of the carbon plus the oxygen

c)

equal to the mass of the carbon

d)

less than the mass of the carbon

42.

The flask and its contents had a mass of 120 grams before the experiment. What would be the mass of the flask and its contents after the experiment?

a)

0 g

b)

60 g

c)

120 g

d)

240 g

43.

In which of the following examples has a chemical reaction occurred?

a)

After putting liquid batter into a hot pan, the batter solidifies and begins to turn brown.

b)

After turning on a blender filled with fruits, the fruit is chopped up and mixed together.

c)

After taking a tray filled with ice cubes out of the freezer, the cubes begin to melt.

d)

After adding a spoonful of sugar to a mug of hot coffee, the sugar dissolves completely.

44.

A physical reaction is:

a)

When the atoms in a substance rearrange to form a new substance

b)

Formed when two or more atoms bond together

c)

When a substance is changed but the atoms are NOT rearranged.

d)

A material made by chemically altering natural materials

45.

Matter can be neither...

a)

destroyed but it can change form.

b)

created nor destroyed.

c)

created nor destroyed. It just changes form.

d)

created.

46.

Cooking an egg is..

a)

a chemical reaction

b)

a physical reaction

47.

boiling water to make hot cocoa is...

a)

a chemical reaction

b)

a physical reaction

48.
Which is an example of a physical change?
a)
Burning wood
b)
Freezing water
c)
Rust on a car
d)
Cooking food
49.
Which is an example of a chemical change?
a)
Burning wood
b)
Rust on a car
c)
Cooking food
d)
All of the above
50.

Which of the following is NOT a sign of a chemical reaction occurring?

a)

Change in temperature

b)

Change in color

c)

Production of gas (bubbles)

d)

Change of state